QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1082
12-BIT/ 14-BIT, 3MSPS SIMULTANEOUS SAMPLING ADC
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DESCRIPTION
LTC1407
Demonstration circuit 1082 features the LTC1407
family of ADCs. This Quick Start Guide will focus on
DC1082A-A which uses the LTC1407A-1, a bipolar, 2-
channel, 14-bit, simultaneous sampling ADC. Total
throughput is 3MSPS; 1.5MSPS per channel, with a
typical channel-to-channel aperture skew of 200ps.
Other family members have 12-bits (LTC1403,
LTC1407, LTC2355-12, and LTC2356-12) or 1-
channel (LTC1403, LTC1403A, LTC2355-14, and
LTC2356-14). The LTC1407 family also has unipolar
and bipolar versions. See Table 1 for the specific
version of the DC1082A that best suits your
application. DC1082A demonstrates the AC
performance of the LTC1407 family in conjunction
with the DC890B Fast DAACS data collection board.
Alternatively, by connecting the DC1082A into a
customer application the performance of the
LTC1407 family member can be evaluated directly in
that circuit.
Design files for this circuit board are available.
Call the LTC factory.
LTC is a trademark of Linear Technology Corporation
Figure 1. DC1082A connections
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1082
12-BIT/ 14-BIT, 3MSPS SIMULTANEOUS SAMPLING ADC
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Table 1.
DC1082A Configuration Summary
VERSION PART # OF BITS INPUT RANGE SAMPLE RATE # OF CHANNELS
DC1082A-A LTC1407ACMSE-1 14 ±1.25V 3Msps(1.5Msps/Ch) 2
DC1082A-B LTC1407ACMSE 14 0V-2.5V 3Msps(1.5Msps/Ch) 2
DC1082A-C LTC1403ACMSE-1 14 ±1.25V 2.8Msps 1
DC1082A-D LTC1403ACMSE 14 0V-2.5V 2.8Msps 1
DC1082A-E LTC2356-14CMSE 14 ±1.25V 3.5Msps 1
DC1082A-F LTC2355-14CMSE 14 0V-2.5V 3.5Msps 1
QUICK START PROCEDURE
Connect DC1082A to a DC890B USB High Speed Data
Collection Board using connector J3. Connect
DC890B to a host PC with a standard USB A/B cable.
Apply 5V-7V DC to the VIN and GND terminals. Apply
a low jitter signal source to J1(CH0) and J2(CH1) if
applicable. Both J1 and J2 if included, are terminated
with 50 ohms to ground. As a clock source, apply a
low jitter 51MHz (50.5MHz for LTC1403, 63MHz for
LTC2355 and LTC2356) 3.3Vp-p sine wave or square
wave to connector J4. Note that J4 has a 50-ohm
termination resistor to ground. Run the QuickEval-II
software (Pscope.exe version K46 or later) supplied
with DC890B or download it from www.linear.com.
Complete software documentation is available from
the Help menu. Updates can be downloaded from the
Tools menu. Check for updates periodically as new
features may be added.
SOFTWARE CONFIGURATION
The Pscope software should recognize DC1082A and
configure itself automatically. If using an older version
of Pscope and updates are not possible, manual
configuration will be necessary.
In the Configure menu deselect AutoConfigure and
select DC890 Fast DAAQS Controller. Select Configure
again and select Device. Select User Configure, 14-Bits,
Alignment 14, Serial and 1- or 2-Channels depending
on the version of DC1082A
being used. Check Positive-Edge Clk and if applicable,
Bipolar. This is shown in Figure 2.
Click the Collect button (See Figure 3) to begin
acquiring data. Depending on which board was
previously used by Pscope it may be necessary to
press Collect a second time. The Collect button then
changes to Pause, which can be used to pause data
acquisition.
Complete software documentation is available from
the Help menu item, as new features may be added
periodically.
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1082
12-BIT/ 14-BIT, 3MSPS SIMULTANEOUS SAMPLING ADC
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Figure2. User Configure Menu
HARDWARE SET UP
SIGNAL CONNECTIONS
J1-J2 SMA connectors for CH0 and CH1 are
differential inputs. These inputs have 50-ohm
termination resistors. Limit input voltage swings to
2.5Vpp. For optimum performance the input should
be bandlimited to the frequencies of interest. These
signals are capacitively coupled to the ADC inputs as
shipped from the factory. If the DC level of the signal
applied is important JPC-JPF must be properly
configured. See schematic for details.
J3 FastDAACS interface. Connect to DC890B.
J4 Conversion Clock Input. This input has a 50-ohm
termination resistor, and is intended to be
driven by a low jitter, 3.3Vpp sine or square wave. To
achieve full AC performance of this
part, the clock jitter should be kept under 2ps. This
input is capacitively coupled so that the input clock
can be either 0V-3.3V or ±1.65V so that level shifting
is not required. To run at maximum conversion rate,
apply a 51MHz signal for the LTC1407 or 50.5MHz
signal for the LTC1403 to this input. For the LTC2355
and LTC2356 apply a 63MHz signal to achieve the
maximum conversion rate.
GROUNDING AND POWER CONNECTION
Connect a 5V to 7V power supply to the Vin and GND
turret posts. For optimum performance, this supply
should be floating with respect to any signal
generators connected to the analog inputs (J1-J2).
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1082
12-BIT/ 14-BIT, 3MSPS SIMULTANEOUS SAMPLING ADC
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Figure3 DC1082A Screenshot
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1082
12-BIT/ 14-BIT, 3MSPS SIMULTANEOUS SAMPLING ADC
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QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1082
12-BIT/ 14-BIT, 3MSPS SIMULTANEOUS SAMPLING ADC
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